Keithw, I'll answer in the opposite direction.
When we started expediting, we had little money and no experience with straight trucks unless they had 18 wheels. We needed to get in on the cheap (plus we didn't know if this idea was workable), but more important, we had no idea how a truck should be setup, so we bought one that already was successful. We have no regrets about buying that used truck, and we learned a lot in the process.
Our second truck was also a used truck as we continued learning and preserved our cash, as the industry was in a flux at the time. Now we are looking for a third truck, with the industry in a flux again and 7 years under our belts. Yep, we're looking used again.
Vernon